Effects of Tropical Saltmarsh Patches on the Structure of Benthic Macrofaunal Assemblages

Habitat complexity can affect assemblage abundance, richness and composition by providing resources and mediating ecological interactions for an array of organisms in many ecosystems. Temperate saltmarshes are well studied, but little is known about tropical saltmarshes. Here we tested if the presence of saltmarsh patches would increase macrofaunal richness, abundance and influence the structure of macrofaunal assemblages when compared to non-vegetated tidal flats. Macrofaunal abundance was higher in vegetated than in non-vegetated areas, but richness did not differ among areas. Macrofaunal assemblage structure was significantly different among areas and composition differed mainly due to greater abundances of epifaunal species in vegetated areas. Within saltmarshes, the macrofaunal composition generally had greater variability than in non-vegetated areas, likely due to greater habitat complexity generating different environmental conditions. Additionally, megalopa and juvenile individuals of Leptuca leptodactyla were more abundant in vegetated areas indicating that tropical saltmarshes may have an important role as a nursery ground for fiddler crabs. This study increased knowledge of tropical saltmarsh patterns and suggests that further research should test the ecological roles of tropical saltmarshes, such as a nursery.